1. Field of the Invention
The invention relates to a cap for a bottle-stopping device, where the device comprises a main body member and the cap, and where the cap is mounted on the main body member, the main body member being provided with retaining tabs, so that the cap presses the tabs against the bottle neck by means of a side wall. This side wall has an upper portion and a lower portion.
2. Description of the Related Art
Bottle stoppers are known that are effected by means of a ferrule of metallic material. They are used to stopper all kinds of bottles or flasks having a neck provided with an outer annular rim in the upper edge of the neck. The top of the outer annular rim is usually flat and flush with the upper edge of the neck and the lower portion thereof is attached to the outer side surface of the neck at an intermediate point thereof. The ferrule is a metallic member that usually comprises a flat annular portion, and a cylindrical portion, attached to the flat annular portion at an outer end thereof and perpendicular to said flat annular portion. When the ferrule is mounted on the bottle or flask, the flat annular portion bears on the outer annular rim, or on an elastic ring whose function is to improve the tightness of the stopper and which is deposited, in this case, on the outer annular rim. In any case, the flat annular portion is substantially parallel to the upper end of the outer annular rim. The cylindrical portion then surrounds the outer annular rim on the outside thereof. It is then necessary to carry out an operation pressing said cylindrical portion against the outer annular rim, deforming it and thereby attaching the ferrule to the bottle.
This process has a number of drawbacks, one of which is the cost thereof, both of the materials used and of the operations required for carrying out the stopping of a bottle.
There are also bottle stopping devices that comprise a main body member of plastics material with a annular portion to be mounted parallel to the upper edge of the neck, tabs directed downwardly from the outer edge of the annular portion, and a substantially cylindrical jacket or cap, adapted for sliding over the tabs. Each tab is provided with a projection that, when the jacket is placed over the tabs, is positioned exactly under the outer annular rim.
In the patent application ES P9900578 and in the application of patent of addition ES P200000557 that are incorporated herein by reference, examples of bottle stopper devices are described. The caps of the prior art devices are usually mounted on the main body member with a force sufficient to bend the tabs and press them tightly against the bottle neck. In this way the cap is fixed on the main body member by the frictional force existing between the cap and the tabs. However, in certain cases, this frictional force is insufficient, and it is possible to remove the cap again and consequently, to disassemble the main body member. It is therefore desirable to endow the bottle stopper device with a mechanism preventing removal of the cap, once mounted, or at least making removal very difficult.
In this sense, it is possible to endow the cap with internal protuberances that increase the frictional force between the cap and the main body member, such as for example in the caps described in the document EP 0 704 251 A.
In other cases, a snap-fit mechanism is included in the bottle stopper device, in the form of a shoulder provided inside the cap against which the tabs are retained.
However, these solutions have aesthetic effects that can be undesired and/or have reduced effectiveness.
Another drawback of the known caps is that the lower end thereof is usually a sharp edge. This sharp edge can cause cuts in the personnel and can hinder the sliding movement of the caps when mechanical means are used. This obliges this sharp edge to be rounded.
It is an object of the invention to overcome these drawbacks simply and simultaneously, with a reduced economic cost. This aim is achieved by a cap for a bottle stopping device of the type first mentioned above wherein said side wall at said lower portion is provided with an end portion folded back 180xc2x0 over itself toward the inside, in such a way as to define an inner shoulder for retaining said tabs.
Indeed, in this way, all the previously mentioned drawbacks are simultaneously solved by a single bending operation. An excellent hold is achieved, since the snap-fit is stronger than a simple frictional hold. A rounded lower edge of the cap is achieved which is, therefore, appropriate for manipulation and for sliding movement. The fold is internal, whereby it is invisible from the outside and it does not affect the aesthetic aspect. Additionally, the rounded lower end facilitates the operation of mounting the cap on the main body member.
The side wall is preferably thinner at said lower portion than at said upper portion. In this way the height of the shoulder can be lower than in the case where the wall is of constant thickness. In this way the snap-fit properties can be better combined with the force required for mounting the cap on the main body member that, with a shoulder of great height, would require an excessively high force, and could even damage the main body member. In particular, the optimum height ranges between 0.05 and 0.40 mm.
One particularly advantageous embodiment of the invention is obtained when the cap is provided with a recess adjacent said shoulder. Indeed, the cap presses and resiliently and plastically deforms the main body member. With the existence of a recess, the main body member (precisely the ends of the tabs) can expand slightly outwardly, partially occupying the recess. In this way the interference height between the main body member and the cap is greater than simply the height of the shoulder, since the distance that the ends of the tabs have expanded toward the recess is added thereto. This recess is preferably obtained by a side wall having two thicknesses, a first thickness at the upper portion and a second thickness at the lower portion, so that the recess is formed by leaving a free space between the upper portion and the folded free end of the lower portion.
Another particularly advantageous embodiment of the invention is obtained when the side wall is provided with three differentiated thicknesses: a first thickness at the upper portion, a second thickness at an intermediate side wall portion of the lower portion that is adjacent the upper portion, the second thickness being smaller that the first thickness, and a third thickness at the side wall end portion folded back towards the inside, said third thickness being smaller than said second thickness. In this way, the third thickness makes it easier to fold the end portion of the cap back towards the inside.